Pompe's disease is a well recognized glycogen storage disease of humans. Glycogen is deposited in tissues and there is an associated deficiency of alpha-1, 4-glucosidase. There is little detailed information on the pathogenesis of the lesions. The school of Veterinary Studies at Murdoch University has acquired a unique herd of cattle carrying a genetic defect which is expressed in homozygous animals in the form of Pompe's disease. To date the syndrome has only been seen in young adults but a juvenile form may exist. We aim to continue to produce affected animals so that we may study the precise clinical manifestations of the condition and to study the development of the lesions, biochemically and by light and electron microscopy. This will be done by performing serial biopsies on muscle, liver, nerve and gut and by performing detailed postmortem examinations on animals showing overt signs of disease. The biochemical and morphological changes will be related. A major long-term aim is to investigate the feasibility of enzyme replacement therapy by establishing chimeras and by the administration of alpha-1, 4-glucosidase prepared from normal individuals.